log magento 1.9 code example

Example 1: mage log magento 2

addWriter($writer);
  $logger->info('Simple Text Log'); // Simple Text Log
  $logger->info('Array Log'.print_r($myArrayVar, true)); // Array Log
?>

Example 2: log magento 1

Mage::log('message',null,'logfile.log',true);

Example 3: mage log equivalent magento 2

\Magento\Framework\App\ObjectManager::getInstance()->get(\Psr\Log\LoggerInterface::class)->debug('Your message here');